(CNN) -- Until this week, Republican presidential candidate Mike Huckabee had not run a single ad in Michigan, and had no paid staffers in the state.

Mike Huckabee is hoping evangelicals and Fair Tax advocates bring him another win in Michigan.

He did not have a campaign office. He had not sent out a single piece of direct mail.Meanwhile, his rival Mitt Romney -- who announced after his second-place New Hampshire showing that Michigan was his top priority -- has run nearly $3 million dollars worth of television ads in Michigan.

And John McCain, fresh off his New Hampshire win -- and with the backing of two of the state's largest papers, the Detroit News and the Detroit Free-Press -- has been keeping pace in recent polls with the well-funded Romney effort.

But just as in Iowa, a grassroots network of conservative Christian activists and fair tax proponents are, improbably, keeping Huckabee in contention for the top spot in the GOP primary here.

"We laid the groundwork," says Gary Glenn, one of the leaders of the movement. "The fact that he's even in a position to threaten Mitt Romney in his native state is a real statement to the depth of support he has here."

Huckabee's been riding a months-long wave of good news in Michigan. Just before Labor Day, the International Association of Machinists and Aerospace Workers made him their pick in his party's presidential primary -- a rare nod to a GOP candidate that might not mean much in other Republican contests, but carries some weight in this heavily unionized state.

The Fair Tax movement -- which has given Huckabee its enthusiastic backing -- announced a major political push in Michigan in 2008, looking to get an anti-tax measure on the ballot this fall.

LaMar Lemmons, the Detroit state representative who helped organize the successful Democratic crossover effort that helped McCain beat Bush here in 2000, recently launched Democrats for Huckabee -- the sort of group that can make a real difference in a state where the lack of party registration allows for large-scale crossover voting.